This section provides background information related to the present disclosure and is not necessarily prior art. Some automotive vehicles and other machines powered by an internal combustion engine may include a selective catalytic reduction (SCR) system in which a substance such as urea, for example, is injected into exhaust gas discharged by the engine. The urea reacts with the exhaust gas and converts harmful pollutants in the exhaust gas to more benign compounds, thereby subjecting the environment to fewer pollutants than without urea injection.
Urea is susceptible to freezing in cold weather and can be adversely affected by extreme heat generated by the engine and/or other vehicle systems. A temperature control system may be provided to maintain the urea within a predetermined temperature range.